Some operating environments for semiconductor devices (for example, complementary metal-oxide semiconductor (CMOS) devices) require that the semiconductor devices be resistant to radiation. For example, space and military operating environments may expose semiconductor devices to radiation. Exposure to radiation can cause conventional semiconductor devices, which are not radiation-hardened to malfunction or even destruct. For example, radiation passing through semiconductor devices deposits energy or causes charged locations within the components, and changes how a device may respond. Devices may be turned on or off, capacitors may be inadvertently charged, memory cells may change state (0 to 1, 1 to 0) corrupting data, and processors may latch up, causing circuit burnout. However, known radiation-tolerant and radiation-hardened semiconductor devices are typically more costly to produce, less energy efficient, and have higher operational costs than non-radiation-tolerant parts.
Semiconductor devices including silicon-on-insulator (SOI) substrates generally exhibit a higher radiation tolerance and lower power consumption than semiconductor devices formed on a monolithic silicon substrate. The smaller volume of silicon on the SOI substrate, and reduced electronic part cross-section, improve resistance to radiation-induced single-event upset. However, the SOI substrate may still be prone to radiation-induced failure due to positive charge buildup within the insulator material. The positive charge buildup results in increased device leakage and threshold voltage shifts. In current SOI devices, the probability of radiation damage due to build-up of radiation damage in the insulator substrate is now a significant portion of the overall probability of radiation damage.
Accordingly, additional improvements in radiation-hardness are desirable, especially for long-term usage of semiconductor devices in harsh environments such as outer space, nuclear reactors, and particle accelerators.